I've tried some further diagnostics, i had someone hold the fuel tap while i held the carby and manipulated the float. The needle was closing ok. I noticed though that the spindle holding the float came off easily. I had some brazing rod so i cut up a bit and its now a nice tight fit within the carby body. I reassembled it and put it back onto the mower. I pulled the cord a few times and left the mower out in the sun for a few hours and it started but died soon after. Tried a few more times and it ran for several secs, best result yet, the throttle had no effect on the revs and it sounded like it needed more revving but i couldnt give it any more because of the governor. I tried a few more times to get it started but it wouldnt. Now have i got a flooding problem or is carby blocked again?